Surface analysis of new Microcarriers Tailored for Cell Therapy

Several clinical studies have reported the benefit of the administration of Mesenchymal stromal cells (MSC) in various cell therapies. However, these studies have also highlighted that their routine application need urgently new cell substrates to multiply MSC in vitro in GMP conditions. Indeed, MSC are scarce in the human body. It is therefore necessary to amplify MSC in vitro to achieve clinically relevant cell doses. Microcarriers are attractive substrate. However, in practice, MSC cultivation on the microcarriers currently available on the market has been demonstrated unsuccessful.
The main aim of our research relies upon the optimization of the surface properties of microcarriers promoting MSC culture in vitro. To achieve this purpose, the outer surface of microcarriers is functionalized by grafting a thin layer composed of a “smart polymer”, mostly poly N-isopropylacrylamide (pNIPAM), whose composition has been tailored to promote the adhesion and spreading of MSC with the ability to control their fast and efficient detachment following a small change in temperature.
Due to particular shape of microcarriers, specific microscopy technique must be adapted to analyse the efficiency of grafting reaction. At this stage, we have demonstrated some reliable characterization methods based on Time-of-Flight and Nanoscale Secondary Ion Mass Spectrometry (ToF and NanoSIMS), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Fluorescent Microscopy for two type of microcarriers: Dextran and Polystyrene based carriers